Optimisation and modelling of supercritical CO2 extraction process of carotenoids from carrot peels

Abstract

This work aimed to assess and optimise the extraction of carotenoids from carrot peels by supercritical CO2 (S-CO2), utilising ethanol as co-solvent. The evaluated variables were temperature, pressure and co-solvent concentration. According to the validated model, the optimal conditions for maximum mass yield (5.31%, d.b.) were found at 58.5°C, 306bar and 14.3% of ethanol, and at 59.0°C, 349bar and 15.5% ethanol for carotenoid recovery (86.1%). Kinetic experiments showed that 97% of the total extractable carotenoid content was recovered after only 30min, whereas model fitting confirmed the fast extraction trend and desorbing nature of carotenoids from the sample matrix. The process is potentially scalable, as demonstrated by runs performed with a 10-fold initial sample size, which led to even higher recoveries (96.2%), indicating that S-CO2 can be as efficient as a conventional solvent extraction for recovering high value compounds from vegetable by-products.